Tower crane movement control method, apparatus, computing device, and storage medium

Abstract

The embodiment of the application relates to the technical field of intelligent construction, and relates to a tower crane motion control method, device, equipment and medium. The scheme of the tower crane motion control method is as follows: obtaining an original planning track from a planner of a tower crane; obtaining start delay time in each axis direction of the tower crane; respectively shifting the track points on the original planning track in each axis direction as a whole according to the start delay time in each axis direction, and synchronizing the start time in each axis direction, so that each axis reaches the same expected position at the same time. The embodiment of the application controls the motion of the tower crane according to the actual working condition and the dynamic characteristics of the tower crane, and the control model is adapted to the working condition and the dynamic characteristics of the real tower crane through the shaft action start delay shift processing, so that the tower crane operation control is more accurate, and the safety risk is effectively reduced.

Description

Technical Field

[0001] This invention relates to the field of intelligent construction technology, and in particular to tower crane motion control methods, devices, computing equipment, and storage media. Background Technology

[0002] Tower cranes are widely used in building and infrastructure construction. Traditional tower crane control requires a driver and a ground-based supervisor, resulting in high labor intensity and safety risks. In recent years, the construction industry has been exploring ways to achieve unmanned tower cranes, but most methods simply eliminate the need for a high-altitude operator, replacing it with cloud-based control from the ground. For example, fuzzy control, sliding mode control, genetic algorithms, and neural networks are used to build models in laboratory environments for simulation, aiming for precise control of unmanned tower cranes. However, existing control models differ significantly from the dynamic characteristics of real tower cranes, and the operating conditions of real tower cranes are much more complex. Therefore, existing control models are not well-suited to the operating conditions and dynamic characteristics of real tower cranes, limiting the control accuracy of unmanned tower cranes and preventing the achievement of precise control. Summary of the Invention

[0003] In view of the above-mentioned problems of the prior art, the embodiments of this application provide a tower crane motion control method, device, computing equipment and storage medium, which performs motion control on the tower crane according to the actual working conditions and dynamic characteristics of the tower crane. By processing the shaft movement start delay misalignment, the control model is adapted to the actual working conditions and dynamic characteristics of the tower crane, thereby making the tower crane operation control more precise and effectively reducing safety risks.

[0004] To achieve the above objectives, the first aspect of this application provides a tower crane motion control method, comprising:

[0005] Obtain the original planning trajectory from the tower crane's planner;

[0006] Obtain the start-up delay time in each axis direction of the tower crane;

[0007] According to the start-up delay time in each axis direction, the trajectory points on the original planned trajectory are shifted and misaligned as a whole in each axis direction to align the start-up time in each axis direction, so that each axis reaches the same desired position at the same time.

[0008] As one possible implementation of the first aspect, the method further includes:

[0009] During tower crane operation, determine whether the tower crane is moving in the direction of its slewing axis;

[0010] When there is movement in the direction of the slewing axis, the brake in the direction of the slewing axis is released at a predetermined time before the command speed in the direction of the slewing axis is issued.

[0011] As one possible implementation of the first aspect, the method further includes:

[0012] When there is no movement in the direction of the slewing axis, the movement in the direction of the slewing axis is controlled by jogging the brake.

[0013] As one possible implementation of the first aspect, the method further includes:

[0014] Determine whether the tower crane's slewing axis is in the correct position.

[0015] When the object is in the correct operating position in the direction of the slewing axis, the hook is lowered.

[0016] As one possible implementation of the first aspect, it is characterized by...

[0017] After obtaining the original planning trajectory from the tower crane's planner, the method further includes: adapting the planning speed of each trajectory point on the original planning trajectory of the tower crane to a gear to obtain a discretized planning trajectory;

[0018] The step of translating and misaligning the trajectory points on the original planned trajectory in each axial direction to equalize the start time in each axial direction further includes: translating and misaligning the trajectory points on the discretized planned trajectory according to the start delay time in each axial direction to equalize the start time in each axial direction.

[0019] As one possible implementation of the first aspect, the step of adapting the planned speed of each trajectory point on the original planned trajectory of the tower crane to a gear to obtain a discretized planned trajectory includes:

[0020] Determine the speed separation between adjacent operating gears based on the speed of each operating gear of the tower crane.

[0021] Obtain the planning velocity of each trajectory point on the original planned trajectory;

[0022] Based on the gear separation speed, the gear speed that matches the planned speed is obtained;

[0023] For each trajectory point on the original planned trajectory, the planned speed is replaced with the adapted gear speed to obtain the discretized planned trajectory.

[0024] As one possible implementation of the first aspect, after translating and misaligning the trajectory points on the original planned trajectory along each axis to align the start times in each axis, the method further includes:

[0025] During the operation of the tower crane, it is determined whether the motion state in the axial direction meets the corresponding PID control start-up conditions; wherein, the corresponding PID control start-up conditions are set in advance according to the motion characteristics in the axial direction.

[0026] When the motion state in the axial direction meets the corresponding PID control start-up conditions, the target speed planned for the next trajectory point is compensated; and the compensated target speed is discretized according to the operating gear of the tower crane to obtain the gear speed that matches the compensated target speed; the matched gear speed is used as the command speed issued for the next trajectory point.

[0027] A second aspect of this application provides a tower crane motion control device, comprising:

[0028] The first acquisition unit is used to acquire the original planning trajectory from the tower crane's planner;

[0029] The second acquisition unit is used to acquire the start-up delay time of the tower crane in each axis direction;

[0030] The delay processing unit is used to perform overall translation and misalignment of the trajectory points on the original planned trajectory in each axis direction according to the start delay time in each axis direction, so as to align the start time in each axis direction and make each axis reach the same desired position at the same time.

[0031] As a possible implementation of the second aspect, the device further includes a slewing control unit, the slewing control unit being used for:

[0032] During tower crane operation, determine whether the tower crane is moving in the direction of its slewing axis;

[0033] When there is movement in the direction of the slewing axis, the brake in the direction of the slewing axis is released at a predetermined time before the command speed in the direction of the slewing axis is issued.

[0034] As one possible implementation of the second aspect, the slewing control unit is further configured to:

[0035] When there is no movement in the direction of the slewing axis, the movement in the direction of the slewing axis is controlled by jogging the brake.

[0036] As a possible implementation of the second aspect, the device further includes a hook lowering control unit, the hook lowering control unit being used for:

[0037] Determine whether the tower crane's slewing axis is in the correct position.

[0038] When the object is in the correct operating position in the direction of the slewing axis, the hook is lowered.

[0039] As a possible implementation of the second aspect, the device further includes a discrete processing unit, which is used to: after obtaining the original planning trajectory from the tower crane's planner, perform gear-adaptation on the planning speed of each trajectory point on the original planning trajectory of the tower crane to obtain a discretized planning trajectory.

[0040] The delay processing unit is further configured to: shift and misalign the trajectory points on the discretized planned trajectory as a whole according to the start delay time in each axis direction, so as to align the start time in each axis direction.

[0041] As one possible implementation of the second aspect, the discrete processing unit is used for:

[0042] Determine the speed separation between adjacent operating gears based on the speed of each operating gear of the tower crane.

[0043] Obtain the planning speed of each trajectory point on the original planned trajectory;

[0044] Based on the gear separation speed, the gear speed that matches the planned speed is obtained;

[0045] For each trajectory point on the original planned trajectory, the planned speed is replaced with the adapted gear speed to obtain the discretized planned trajectory.

[0046] As a possible implementation of the second aspect, the device further includes a PID control unit, the PID control unit being used for:

[0047] During the operation of the tower crane, it is determined whether the motion state in the axial direction meets the corresponding PID control start-up conditions; wherein, the corresponding PID control start-up conditions are set in advance according to the motion characteristics in the axial direction.

[0048] When the motion state in the axial direction meets the corresponding PID control start-up conditions, the target speed planned for the next trajectory point is compensated; and the compensated target speed is discretized according to the operating gear of the tower crane to obtain the gear speed that matches the compensated target speed; the matched gear speed is used as the command speed issued for the next trajectory point.

[0049] A third aspect of this application provides a computing device, comprising:

[0050] Communication interface;

[0051] At least one processor connected to the communication interface; and

[0052] At least one memory connected to the processor and storing program instructions that, when executed by the at least one processor, cause the at least one processor to perform the method described in any of the first aspects above.

[0053] A fourth aspect of this application provides a computer-readable storage medium having program instructions stored thereon, which, when executed by a computer, cause the computer to perform the method described in any of the first aspects above.

[0054] These and other aspects of the invention will become more apparent from the following description of several embodiments. Attached Figure Description

[0055] The various features of the present invention and the relationships between them are further explained below with reference to the accompanying drawings. The drawings are exemplary; some features are not shown to scale, and some drawings may omit conventional features in the field of this application that are not essential to this application, or additional features that are not essential to this application may be shown. The combination of features shown in the drawings is not intended to limit the present application. Furthermore, throughout this specification, the same reference numerals refer to the same things. Specific descriptions of the drawings are as follows:

[0056] Figure 1A This is a structural diagram illustrating the application scenarios of various embodiments of this application;

[0057] Figure 1B This is a schematic diagram of the tower crane used in various embodiments of this application;

[0058] Figure 2 This is a schematic diagram of an embodiment of the tower crane motion control method provided in this application.

[0059] Figure 3 This is a schematic diagram illustrating the execution flow of an embodiment of the tower crane motion control method provided in this application.

[0060] Figure 4 A schematic diagram of the discretization process of an embodiment of the tower crane motion control method provided in this application;

[0061] Figure 5 An example diagram showing the data calculation results of the gear speed and gear separation speed in one embodiment of the tower crane motion control method provided in this application;

[0062] Figure 6 This is a schematic diagram of the discrete algorithm flow of an embodiment of the tower crane motion control method provided in this application.

[0063] Figure 7A schematic diagram of the PID control flow of an embodiment of the tower crane motion control method provided in this application;

[0064] Figure 8 A PID control diagram of an embodiment of the tower crane motion control method provided in this application;

[0065] Figure 9 This is a schematic diagram of the startup process of an embodiment of the tower crane motion control method provided in this application.

[0066] Figure 10 A schematic diagram of the PID control flow of an embodiment of the tower crane motion control method provided in this application;

[0067] Figure 11 A schematic diagram of the PID control flow of an embodiment of the tower crane motion control method provided in this application;

[0068] Figure 12 A schematic diagram of the PID control flow of an embodiment of the tower crane motion control method provided in this application;

[0069] Figure 13 A schematic diagram of the discretization process of an embodiment of the tower crane motion control method provided in this application;

[0070] Figure 14 A schematic diagram of an embodiment of the tower crane motion control device provided in this application;

[0071] Figure 15 A schematic diagram of an embodiment of the tower crane motion control device provided in this application;

[0072] Figure 16 A schematic diagram of a computing device provided in an embodiment of this application. Detailed Implementation

[0073] The terms "first, second, third, etc." or similar terms such as module A, module B, module C, etc., used in the specification and claims are only used to distinguish similar objects and do not represent a specific ordering of objects. It is understood that a specific order or sequence may be interchanged where permitted so that the embodiments of this application described herein can be implemented in an order other than that illustrated or described herein.

[0074] In the following description, the labels of the steps, such as S110, S120, etc., do not necessarily mean that the steps will be executed in this way. The order of the steps can be interchanged or executed simultaneously if permitted.

[0075] The term "comprising" as used in the specification and claims should not be construed as limiting itself to what follows; it does not exclude other elements or steps. Therefore, it should be interpreted as specifying the presence of the mentioned feature, integral, step, or component, but does not exclude the presence or addition of one or more other features, integrals, steps, or components, or groups thereof. Thus, the statement "device comprising means A and B" should not be limited to a device consisting solely of components A and B.

[0076] The term "an embodiment" or "an embodiment" as used in this specification means that a particular feature, structure, or characteristic described in conjunction with that embodiment is included in at least one embodiment of the invention. Therefore, the terms "in one embodiment" or "in an embodiment" appearing throughout this specification do not necessarily refer to the same embodiment, but may refer to the same embodiment. Furthermore, in one or more embodiments, the particular features, structures, or characteristics can be combined in any suitable manner, as will be apparent to those skilled in the art from this disclosure.

[0077] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. In case of any inconsistency, the meaning set forth in this specification or derived from the content described herein shall prevail. Furthermore, the terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit this application. To accurately describe the technical content of this application and to accurately understand the invention, the following explanations or definitions of the terms used in this specification are provided before describing specific embodiments:

[0078] 1) Variable-frequency drive (VFD): A VFD is a power control device that uses frequency conversion technology and microelectronics to control an AC motor by changing the frequency of the power supply. A VFD mainly consists of a rectification unit (AC to DC), a filter, an inverter (DC to AC), a braking unit, a drive unit, a detection unit, and a microprocessor unit. The VFD adjusts the voltage and frequency of the output power supply by switching its internal IGBTs (Insulated Gate Bipolar Transistors), providing the required power voltage according to the actual needs of the motor, thereby achieving energy saving and speed regulation. In addition, VFDs have many protection functions, such as overcurrent, overvoltage, and overload protection.

[0079] 2) TCP (Transmission Control Protocol): A connection-oriented, reliable, byte-stream-based transport layer communication protocol. TCP is designed to adapt to layered protocol hierarchies that support multiple network applications. Pairs of processes in host computers connected to different but interconnected computer communication networks rely on TCP for reliable communication services. TCP assumes that it can obtain simple, potentially unreliable datagram services from lower-level protocols. In principle, TCP should be able to operate over a variety of communication systems, from hardwired connections to packet-switched or circuit-switched networks.

[0080] 3) PID (Proportion-Integral-Derivative): In engineering practice, the most widely used regulator control law is proportional-integral-derivative control, abbreviated as PID control, also known as PID regulation. When the structure and parameters of the controlled object cannot be fully understood, or an accurate mathematical model cannot be obtained, and other techniques of control theory are difficult to apply, the structure and parameters of the system controller must be determined based on experience and on-site debugging. In this case, PID control technology is the most convenient. That is, when we do not fully understand a system and the controlled object, or cannot obtain system parameters through effective measurement methods, PID control technology is most suitable. The PID controller calculates the control quantity based on the system error using proportional, integral, and derivative terms.

[0081] The existing methods will be introduced first, and then the technical solution of this application will be described in detail.

[0082] Tower cranes are widely used in building and infrastructure construction. Traditional tower crane control requires a driver and a ground-based supervisor, resulting in high labor intensity and safety risks. In recent years, the construction industry has been exploring ways to achieve unmanned tower cranes, but most methods simply eliminate the need for a high-altitude operator, replacing it with cloud-based control from the ground. For example, fuzzy control, sliding mode control, genetic algorithms, and neural networks are used to build models in laboratory environments for simulation, aiming for precise control of unmanned tower cranes. However, existing control models differ significantly from the dynamic characteristics of real tower cranes, and the operating conditions of real tower cranes are much more complex. Therefore, existing control models are not well-suited to the operating conditions and dynamic characteristics of real tower cranes, limiting the control accuracy of unmanned tower cranes and preventing the achievement of precise control.

[0083] The existing technology has the following drawbacks: the existing control model is not compatible with the actual working conditions and dynamic characteristics of tower cranes, and the control accuracy of tower cranes is limited.

[0084] Based on the technical problems existing in the prior art, the embodiments of this application provide a tower crane motion control method, device, computing equipment, and storage medium. The tower crane motion is controlled according to the actual working conditions and dynamic characteristics of the tower crane. By handling the shaft movement start delay misalignment, the control model is adapted to the actual working conditions and dynamic characteristics of the tower crane, thereby making the tower crane operation control more precise and effectively reducing safety risks. This solves the technical problem mentioned in the prior art that the existing control model is not compatible with the actual working conditions and dynamic characteristics of the tower crane, and the control accuracy of the tower crane is limited.

[0085] This application provides various embodiments of methods, devices, computing devices, and storage media for tower crane motion control. The following is in conjunction with… Figure 1A and Figure 1B The application scenarios of each embodiment of this application are introduced.

[0086] Figure 1A The control system of the tower crane of this application is shown, which includes video equipment, controller, frequency converter, motor and encoder.

[0087] The video equipment is used to acquire reference points in advance during the operation of the tower crane hook. These reference points include the hook's starting position, target position, and the passable position ahead of any obstacles to be avoided. The coordinates of the reference points acquired by the video equipment are in the user's coordinate system. The video equipment communicates with the controller via the Modbus TCP protocol.

[0088] The electric motor drives the movement of the tower crane hook. The tower crane consists of several axes, representing several adjustment directions. Each axis is driven by a motor.

[0089] The frequency converter receives the planned speed output from the controller and uses it to control the motor speed. One frequency converter is used for control of one axis direction.

[0090] The encoder is used to collect the actual position of the tower crane hook during its movement, helping the hook to avoid obstacles and reach the target position along a planned trajectory. The encoder and controller communicate via the Modbus 485 protocol.

[0091] The controller is used to generate the planned trajectory of the tower crane hook based on the reference point, determine the planned speed of each trajectory point, and drive the tower crane's frequency converter to control the hook to avoid obstacles and accurately reach the target position according to the planned trajectory.

[0092] In this application, each method embodiment runs in a controller, and each device embodiment is deployed in a controller.

[0093] Figure 1BThe illustration shows a tower crane used in various embodiments of this application, which includes three axes: Lift, Turn, and Swing. Lift is also called hoisting, Turn is also called slewing, and Swing is also called luffing.

[0094] in, Figure 1A The mid-video device obtains the coordinates of the tower crane hook in the user coordinate system, which can be converted into... using a transformation matrix. Figure 1B Coordinates in the Cartesian coordinate system.

[0095] Figure 1B The structure is an example of a tower crane. In real-world scenarios, tower cranes may include other numbers of shafts, such as shafts that move laterally and / or longitudinally along guide rails.

[0096] Taking the lifting, rotating, and boom extension axes as an example, during the operation of the tower crane hook, each of the three axes is driven by an AC motor via a frequency converter, and the current position of each axis is collected by an absolute encoder. The vision device transmits the position of the main path point to the controller via Modbus TCP based on the detected obstacle positions. The controller sends motion commands to the three frequency converters via the Modbus 485 bus, while simultaneously collecting the position information from the three encoders.

[0097] Figure 2 This is a schematic diagram of an embodiment of the tower crane motion control method provided in this application. Figure 2 As shown, the method may specifically include:

[0098] Step S110: Obtain the original planning trajectory from the tower crane's planner;

[0099] Step S120: Obtain the start-up delay time in each axis direction of the tower crane;

[0100] Step S130: According to the start-up delay time in each axis direction, the trajectory points on the original planned trajectory are shifted and misaligned as a whole in each axis direction to align the start-up time in each axis direction so that each axis reaches the same desired position at the same time.

[0101] Existing control models are not well-suited to the actual operating conditions and dynamic characteristics of tower cranes. Therefore, a motion control method that can be directly implemented and applied to real-world scenarios is needed. The tower crane motion control method provided in this application is adapted to the actual operating conditions and dynamic characteristics of tower cranes, achieving a leap from laboratory environments to on-site engineering applications. It combines operational processes and industry standards to build a directly implementable motion control system architecture. Furthermore, this architecture is adaptable to both traditional gear-controlled tower cranes and tower cranes with continuous speed control.

[0102] The tower crane controller's motion control software system includes a planner. The planner generates the original planned trajectory of the tower crane hook based on reference points, determines the planned speed at each trajectory point, and drives the tower crane's frequency converter to control the hook to run according to the planned trajectory. In this embodiment, a process package module is included in the tower crane controller. Specifically, the tower crane motion control method provided in this embodiment is run within the controller's process package module. In step S110, the process package module obtains the original planned trajectory from the tower crane's planner. In subsequent steps, further analysis and processing are performed based on the original planned trajectory to achieve precise control of the tower crane's motion.

[0103] Axis movement delay is a unique dynamic characteristic of tower cranes, a type of flexible machinery. The delay occurs because, after the trajectory is planned, the positions of the three axes at each moment on the trajectory point are different. In other words, the movements of the three axes are asynchronous. For example, each of the three axes has 2000 trajectory points. If the first trajectory point is reached when all three axes send a speed of level 1, the response times of the three axes after this speed is sent are different; that is, the start-up delay times of the three axes are not the same. In one example, the lifting axis starts moving 2 seconds after the speed is sent, but the slewing axis starts moving 10 seconds after the speed is sent. Therefore, if no delay processing is applied after the trajectory is planned, the movements of the tower crane's axes will be asynchronous. Given that the start-up delay times of each axis are different and they cannot reach the planned trajectory point simultaneously, in this embodiment, the start-up delay time of each axis of the tower crane can be measured in advance. In step S120, the process package module obtains the pre-measured start-up delay time in each axis direction of the tower crane.

[0104] The crucial role of trajectory planning is to ensure that all three axes arrive at the planned trajectory points simultaneously, allowing the hook to reach the desired position. For example, when a tower crane moves, it has movement in three axial directions, and these three axes need to reach the desired position synchronously. Therefore, axis movement start-up delay misalignment processing is required. In step S130, based on the start-up delay time obtained in step S120 for each axis direction, the trajectory points on the original planned trajectory are shifted and misaligned as a whole in each axis direction. By processing the overall translation and misalignment of trajectory points, the start-up times in each axis direction are aligned, allowing each axis to reach the same desired position at the same time. For example, by shifting and misaligning trajectory points, the axis with a slower start-up time starts first, and the axis with a faster start-up time starts later, thus aligning the delays of the three axes. Using this control method can avoid situations where axis movement start-up delays cause inaccurate control and failure to accurately reach the desired position.

[0105] The embodiments of this application control the tower crane's motion based on its actual working conditions and dynamic characteristics. By using shaft movement start-up delay misalignment processing, the control model is adapted to the actual working conditions and dynamic characteristics of the tower crane, thereby making the tower crane's operation control more precise and effectively reducing safety risks.

[0106] The design scheme of the motion control software system may also include the parameter calibration methods for the zero point and proportional coefficient, and the methods for obtaining the kinematic characteristic parameters of each axis of the tower crane. Among these, the parameter calibration of the zero point and proportional coefficient is the foundation for motion control of the tower crane. The specific calibration methods are as follows:

[0107] 1) Zero point calibration:

[0108] 1.1) Lift Axis: When the tower crane's Lift axis moves to a distance relatively close to the bottom of the boom, record the current encoder value Lift_En and the actual distance of the hoisting rope from the bottom of the boom, Lift_An. When the tower crane's Lift axis moves to a distance relatively far from the bottom of the boom, record the current encoder value Lift_Ep and the actual distance of the hoisting rope from the bottom of the boom, Lift_Ap.

[0109] 1.2) Turn Axis: Defines the 0 position of the Turn axis. Normally, at the 0 position of the Turn axis, the direction the tower crane boom points is the positive X-axis direction of the world coordinate system. Rotation on the Turn axis typically involves multiple revolutions. It is recommended to allow sufficient revolutions during calibration. For example, allow 2 to 3 revolutions to the left and right. In one example, allow 2.5 revolutions to the left and 2.5 revolutions to the right. Rotate the Turn axis to a position close to the negative limit, and record the current encoder value Turn_En and the actual rotation radius value Turn_An. Rotate the Turn axis to a position close to the positive limit, and record the current encoder value Turn_Ep and the actual rotation radius value Turn_Ap.

[0110] 1.3) Swing Axis: Move the hook to a position farther from the tower crane's Z-axis, and record the current encoder position Swing_Ep and the actual position of the hook from the tower crane's Z-axis Swing_Ap. Move the hook to a position closer to the tower crane's Z-axis, and record the current encoder position Swing_En and the actual position of the hook from the tower crane's Z-axis Swing_An.

[0111] 2) Proportional coefficient parameter calibration: The encoder value is a pulse count, such as 10000 or 20000. When calibrating the proportional coefficient parameter, the encoder value can be converted to international standard units: meters and radians. Converting the encoder's acquired values ​​to international units allows for matching with the tower crane's axis space. The following formula can be used for calibration:

[0112]

[0113] 2.1) Calculation of Lift_Ratio:

[0114] When the hook descends to the lowest accessible position:

[0115] The encoder value is Ep, and the length of the hoisting rope (distance from the bottom of the boom, assuming the bottom is the reference point) is Ap, in meters.

[0116] When the hook rises to its highest reachable position:

[0117] The encoder value is En, and the length of the hoisting rope (distance from the bottom of the boom) is An, in meters.

[0118] 2.2) Turn_Ratio calculation:

[0119] When the boom rotates forward to its maximum position:

[0120] The encoder value is Ep, and the rotation angle (the tower crane manual specifies the limit angle) is Ap, in radians.

[0121] When the boom rotates to its maximum position in the negative direction:

[0122] The encoder value is En, and the rotation angle (the limit angle is specified in the tower crane manual) is An, in radians.

[0123] 2.3) Swing_Ratio Calculation:

[0124] When the amplitude is adjusted to the furthest reachable position:

[0125] The encoder value is Ep, and the amplitude transformation length (distance from the Z-axis of the tower crane) is Ap, in meters.

[0126] When the amplitude changes to the nearest reachable position:

[0127] The encoder value is En, and the amplitude transformation length (distance from the Z-axis of the tower crane) is An, in meters.

[0128] 3) Obtaining the kinematic parameters of each axis of the tower crane:

[0129] The output speed of the frequency converters on each axis of the tower crane deviates from the actual movement speed, leading to poor path tracking accuracy or increased transient vibration. Therefore, it is necessary to measure the operational characteristics based on the actual tower crane. The single-axis characteristic parameters that need to be measured include: maximum speed, maximum acceleration, and start-up delay time.

[0130] 3.1) Obtaining maximum speed:

[0131] Each axis is manually operated to the highest gear to collect position information, and the maximum speed is calculated based on the position range after the highest speed stabilizes.

[0132] 3.2) Obtaining acceleration (Lift.AccTime, Turn.AccTime, Swing.AccTime):

[0133] The planner needs to plan trajectories based on the kinematic characteristics of each axis, such as maximum speed and maximum acceleration, to ensure synchronized movement of the three axes and synchronized movement to reach achievable positions with the current acceleration. The planner uses speed and acceleration to plan each moment in time and the position each axis will move to. In joint space, path planning is generated based on joint pathpoints. Pathpoints do not contain time information, while trajectory points do. The planner adds time information to pathpoints that previously lacked it. After adding time information, the maximum speed and acceleration can be obtained. Speed ​​is the rate of change of position, and acceleration is the rate of change of speed. Acceleration can be calculated by measuring the time taken to accelerate from zero to maximum speed using a manual transmission; the rate of increase in speed is the acceleration.

[0134] 3.3) Obtaining the startup delay time:

[0135] The start-up delay time is the time between the issuance of a motion command to each axis and the actual start of motion. The start-up delay time can be measured during manual mode, that is, the time period from the issuance of the I / O gear to the detection of an actual position change.

[0136] The design scheme of the motion control software system may also include the implementation method of the operation process. Specific operation processes and implementation methods may include: handling of axis movement start-up delay misalignment, gear adaptation handling, jogging brake, brake release judgment, slewing to position waiting, data recording, etc. These operation processes can be implemented in the controller's process package module.

[0137] The brake release judgment includes: based on the tower crane's characteristics and operating conditions, the brake needs to be engaged when the slewing shaft is stationary, and the brake needs to be released a certain time before the slewing shaft moves. If the brake is not released in advance, but is released simultaneously with the output gear, the slewing shaft will not move. Additionally, the brake also needs to be engaged after the slewing shaft has reached its position.

[0138] In one embodiment, the method further includes:

[0139] During tower crane operation, determine whether the tower crane is moving in the direction of its slewing axis;

[0140] When there is movement in the direction of the slewing axis, the brake in the direction of the slewing axis is released at a predetermined time before the command speed in the direction of the slewing axis is issued.

[0141] Because the tower crane boom is particularly long, it can sway even in a level 2 wind. The slewing shaft is usually braked before it moves. Releasing the brake a predetermined time before the slewing shaft moves allows for precise control of the shaft's movement during subsequent gear shifts, thus improving control accuracy and safety.

[0142] In one example, the preset time can be set to 1 second. Due to the characteristics of the tower crane's slewing shaft movement, the brake cannot be released simultaneously when issuing the speed command. It should be released at least 1 second in advance; otherwise, the inverter will implement protective measures, resulting in the inability to achieve the expected control. First, determine if there is movement in the slewing shaft direction. If there is movement in the slewing shaft direction, release the brake a certain amount of time before sending the speed command. You can release the brake 1 second before issuing the speed command.

[0143] In one embodiment, the method further includes:

[0144] When there is no movement in the direction of the slewing axis, the movement in the direction of the slewing axis is controlled by jogging the brake.

[0145] The operational processes implemented in the process package module also include inching brake application. The purpose of inching brake application is to avoid locking the slewing brake completely in one go, using a brake-release-brake-engage method. This method can relieve mechanical stress, avoid swaying caused by the slewing brake, and reduce mechanical damage to the tower crane's slewing mechanism.

[0146] In one embodiment, the method further includes:

[0147] Determine whether the tower crane's slewing axis is in the correct position.

[0148] When the object is in the correct operating position in the direction of the slewing axis, the hook is lowered.

[0149] The operational processes implemented in the process package module also include rotation to the designated position and waiting. This method meets industry safety requirements, ensuring the hook does not drop if the rotation is not complete. After the slewing shaft reaches its designated position, a brake is applied before the hook drops. This hook-dropping control method mitigates the impact of external factors such as wind on hook-dropping accuracy and safety.

[0150] In one example, PID control can be used to achieve slewing positioning and waiting. For instance, the planned slewing position is 90 degrees; that is, the hook is lowered to place the suspended object on the ground after slewing to 90 degrees. If it is detected that the object has not accurately reached 90 degrees, the hook is not lowered. During operation, the position of the slewing axis is monitored, and if there is a deviation, PID control is used to ensure the object is in the correct position before lowering the hook.

[0151] In one embodiment, after obtaining the original planning trajectory from the tower crane's planner, the method further includes: adapting the planning speed of each trajectory point on the original planning trajectory of the tower crane to a gear to obtain a discretized planning trajectory.

[0152] The step of translating and misaligning the trajectory points on the original planned trajectory in each axial direction to equalize the start time in each axial direction further includes: translating and misaligning the trajectory points on the discretized planned trajectory according to the start delay time in each axial direction to equalize the start time in each axial direction.

[0153] The operational processes implemented in the process package module also include gear adaptation processing. Gear adaptation processing includes: adapting the trajectory path points according to the tower crane's gear speed, ensuring kinematic acceleration and deceleration characteristics and distance accuracy while achieving discretized output according to the gear speed.

[0154] In addition, the operational processes implemented in the process package module also include data recording and planned path execution flow design. Data recording facilitates data acquisition and accident tracing. The planned path execution flow design is as follows: Figure 3 As shown. See also Figure 3 First, step S3.1 is executed to write the path points from the host computer into the inverse kinematics module. Inverse kinematics is the conversion of Cartesian space position to joint space position. The manually set path points are key points in the desired motion path. Several key points in the path can be set on the host computer application side. For example, when raising the hook, if the current position is 20 meters, raise it to 40 meters. A path point can be set at 20 meters, and another at 40 meters. Then, the tower crane can rotate back 90 meters, and this position can also be set as a path point. Finally, the suspended object is lowered.

[0155] See Figure 3Step S3.2: Run the inverse kinematics module to convert the Cartesian space position to the joint space position. Then, step S3.3: Read the joint points and write them to the planner. Joint points are path points in the joint coordinate system. Step S3.4: Run the trajectory planner to generate the trajectory planning result. Then, step S3.5: Write the trajectory planning result to the process package module. Next, step S3.6: Adapt the process package trajectory to the appropriate speed, matching the trajectory path points to the tower crane's speed settings. Step S3.7: Handle the process package trajectory misalignment by applying a delay to the axis movement start time. For tower cranes based on speed control, there is a delay between the issuance of the speed setting and the start of movement for each axis. Therefore, it is not advisable to adjust the PID controller when the tower crane is not moving; PID adjustment should be performed after the start delay time has elapsed. The PID controllers for all three axes need to be delayed before starting. Specifically, for each axis, if the current time is less than the start-up delay time, the starting point in the original planned trajectory is used as the target position for PID control, and the starting point is adjusted. If the current time is greater than or equal to the start-up delay time, the endpoint is adjusted if all trajectory points have been sent; otherwise, the trajectory points are adjusted one by one. In the above start-up process, a series of target positions are misaligned as a whole. After adjusting the start-up delay time for each axis separately, since the start-up delay times of each axis are different, it is still necessary to execute... Figure 2 The process shown involves aligning the start times of each axis, ensuring that axes with slower start times start first, followed by faster start times, so that all axes reach the desired position simultaneously. Then, step S3.8 is executed, where the Turn axis performs a pre-emptive brake release check and timing. In this step, before motion control, it is determined whether there is movement in the slewing axis direction during the entire operation of the tower crane. If there is movement in the slewing axis direction, the brake will be released at a predetermined time before the speed command is issued during subsequent motion control.

[0156] After the above steps are completed, the gear speed adapted to the planned speed has been obtained, the start time of each axis direction has been aligned, and the time for the turn axis to release the brake in advance has been predicted. At this time, the controller can output control commands to drive the motors corresponding to each axis, control the movement in each axis direction to start until all planned points have been reached.

[0157] The original planned trajectory may include several trajectory points, each corresponding to a control cycle. The current cycle is about to issue the control command for the next trajectory point. The target speed of the next trajectory point is calculated by the planner. Throughout the control process, based on the already planned target speed of the next trajectory point, the speed of the command for the next trajectory point can be adjusted in each current cycle to achieve a more precise control effect. Specifically, step S3.9 is executed to control the movement in each axis direction until all planned points have been traversed. The entire movement process includes the following functions:

[0158] 1. Hook-dropping control after rotation to the designated position. For example, if the planned operation is to rotate to a predetermined position and then drop the hook, the position of the rotation axis in the direction of rotation is detected in each current cycle of the operation. If it is detected that the hook has not accurately dropped to the predetermined position, the hook will not drop. If there is a deviation, PID control is used to detect and perform hook-dropping control only after the rotation is in place.

[0159] 2. Slewing Brake Release and Brake Control. In step S3.8, a brake detection and timing were performed in advance for the slewing shaft. If it is determined that movement in the slewing shaft direction will begin at a certain time T, the brake is released in advance a time t before the speed command is sent. For example, if the reserved time t is 1 second, the brake can be released 1 second before the speed command is issued. Therefore, the brake is released in advance within the control cycle of 1 second before time T, and then the speed command is issued at time T.

[0160] 3. Gear PID control: This involves adjusting the gear speed based on the PID control and the command speed issued from the trajectory point. The corresponding PID control start conditions can be pre-set according to the motion characteristics along the axis. During tower crane operation, when the motion state along the axis meets the corresponding PID control start conditions, compensation is applied to the planned target speed for the next trajectory point in the current cycle. The compensated target speed is then converted into the adapted gear speed, which is used as the command speed for the next trajectory point. Throughout the entire control and adjustment process, necessary information can be recorded in an array.

[0161] In highly flexible applications, motion characteristics are not constant throughout the entire motion process. However, modeling such motion characteristics is quite difficult. Therefore, after the entire motion process is completed, i.e., after all command speeds have been sent, a final adjustment process is added, executing step S3.10 to perform PID final adjustment. In one example of PID final adjustment, the tower crane's motion trajectory includes 6 seconds for lifting motion. If the lifting is insufficient, the PID is readjusted to ensure the tower crane finally reaches the desired final position. Finally, step S3.11 is executed to write the necessary data to a file.

[0162] Figure 3 The steps are executed sequentially to ultimately achieve a motion control method that integrates tower crane operation processes.

[0163] See Figure 4 In one implementation, the step of adapting the planned speed of each trajectory point on the original planned trajectory of the tower crane to a gear to obtain a discretized planned trajectory includes:

[0164] Step S410: Determine the gear separation speed between adjacent operating gears based on the gear speed of each operating gear of the tower crane.

[0165] Step S420: Obtain the planning speed of each trajectory point on the original planning trajectory;

[0166] Step S430: Based on the gear separation speed, obtain the gear speed that matches the planned speed;

[0167] Step S440: For each trajectory point on the original planned trajectory, replace the planned speed with the adapted gear speed to obtain the discretized planned trajectory.

[0168] In practical applications, many unmanned tower cranes control their movement based on operating gears. Taking the hoisting, slewing, and luffing axes as examples, each axis has an operating gear or control gear to control the speed of its corresponding mechanism during crane movement. For example, the lever-type operating gear in the crane operator's cab can be used to control the crane's movement. Each gear can have 3 to 5 positions. For instance, when the hoisting axis's operating gear is set to X, the hoisting mechanism rises or falls at the speed corresponding to X; when the slewing axis's control gear is set to Y, the slewing mechanism rotates at the speed corresponding to Y.

[0169] To address the above-mentioned control method based on operating gears, a gear discretization method for the kinematic trajectory is needed. This method ensures that the trajectory satisfies kinematic characteristics while also discretizing the speed output into gear-specific speeds. In the gear-based control method, the gear speed corresponds to discrete values ​​for each operating gear. The controller generates the original planned trajectory of the tower crane hook and determines the planned speed for each trajectory point. However, the planned speeds for each trajectory point do not match the gear speeds for each operating gear. Therefore, it is necessary to assign the planned speeds of each current trajectory point to the gear speeds one by one.

[0170] This application provides a trajectory discretization method for an unmanned tower crane adapted to gear control. For each trajectory point on the original planned trajectory, a suitable gear speed is found to replace the original planned speed, and the original planned trajectory is discretized. After discretization, the control output is adapted to the control method, thereby improving the control accuracy of the unmanned tower crane.

[0171] In step S410, the gear separation speed between two adjacent operating gears is determined based on the gear speed of each operating gear of the tower crane. If the planned speed of a certain trajectory point is less than or equal to the gear separation speed, the relatively lower gear speed is assigned to the trajectory point to obtain the discretized planned trajectory; if the planned speed of a certain trajectory point is greater than the gear separation speed, the relatively higher gear speed is assigned to the trajectory point to obtain the discretized planned trajectory.

[0172] In one example, the tower crane's lifting shaft has three operating speeds: speed 1 is 0.5 m / s, speed 2 is 1 m / s, and speed 3 is 1.5 m / s. A speed value within the range of 0.5 m / s to 1 m / s can be chosen as the speed separating speeds between speeds 1 and 2. For example, 0.75 m / s can be chosen as the speed separating speed between speeds 1 and 2. If the planned speed of a trajectory point is less than or equal to 0.75 m / s, then the speed of speed 1 (0.5 m / s) is assigned to that trajectory point, resulting in a discretized planned trajectory. In other words, the speed that matches the planned speed of that trajectory point is the speed of speed 1 (0.5 m / s). If the planned speed of a trajectory point is greater than 0.75 m / s, then the speed of speed 2 (1 m / s) is assigned to that trajectory point, resulting in a discretized planned trajectory. In other words, the speed that matches the planned speed of this trajectory point is the second gear speed of 1 m / s.

[0173] Similarly, a speed value within the range of 1 m / s to 1.5 m / s can be selected as the gear-separating speed between gear 2 and gear 3. For example, 1.25 m / s can be chosen as the gear-separating speed between gear 2 and gear 3. If the planned speed of a trajectory point is less than or equal to 1.25 m / s, then the gear-separating speed of 1 m / s (gear 2) is assigned to that trajectory point, resulting in the discretized planned trajectory; if the planned speed of a trajectory point is greater than 1.25 m / s, then the gear-separating speed of 1.5 m / s (gear 3) is assigned to that trajectory point as the discretized planned trajectory.

[0174] In step S420, the planned speed of each trajectory point on the original planned trajectory of the tower crane hook generated by the controller is obtained. In step S430, based on the gear separation speed determined in step S410, the gear speed adapted to the planned speed of each trajectory point is obtained. If the planned speed of a trajectory point is between two adjacent gear speeds, the planned speed is compared with the gear separation speed between the two adjacent gear speeds. If the planned speed is less than or equal to the gear separation speed, the gear speed adapted to the planned speed of the trajectory point is a relatively lower gear speed; if the planned speed is greater than the gear separation speed, the gear speed adapted to the planned speed of the trajectory point is a relatively higher gear speed. For example, if the planned speed of a trajectory point is 0.8 m / s, and its speed value is between gear 1 and gear 2 and greater than the gear separation speed between gear 1 and gear 2 (0.75 m / s), then the gear speed adapted to the planned speed of the trajectory point is gear 2 speed (1 m / s).

[0175] In step S440, for each trajectory point on the original planned trajectory, the planned speed in the original planned trajectory is replaced with the adapted gear speed obtained in step S430 to obtain the discretized planned trajectory.

[0176] The above example illustrates the discretization of the trajectory of a tower crane's lifting axis. The same discretization method can be used for each axis of the tower crane to ensure that the control output matches the control method, thereby improving the control accuracy of the unmanned tower crane.

[0177] In summary, the embodiments of this application discretize the trajectory, so that the tower crane trajectory can not only meet the kinematic characteristics, but also discretize the speed output into gear speeds. The trajectory discretization process improves the control accuracy of the tower crane and effectively reduces safety risks.

[0178] In one embodiment, the method further includes:

[0179] Measure the speed of the highest gear in the specified operating gear range;

[0180] The speed of each operating gear is calculated based on the highest gear speed and the Hertz value of the inverter corresponding to each operating gear.

[0181] Discretizing the original planned trajectory requires setting the speed of each axis at each operating gear. In one example, setting the speed of each axis requires first measuring the actual speed of each axis at its highest manual gear. The measured actual speed of the highest gear is the speed of the highest gear. Then, based on the actual speed of the highest gear and the actual Hertz values ​​corresponding to the other gears, the speeds of the other gears are determined. Here, the Hertz value represents the speed of the frequency converter. The Hertz value is marked on each gear in the frequency converter's instruction manual. The Hertz value of each gear can be obtained from the frequency converter's instruction manual. Then, the actual speed corresponding to the Hertz value of the highest gear is measured. Finally, the actual speed corresponding to the Hertz value of each other gear is calculated using a proportional formula, thus obtaining the speeds of the other gears. The method for obtaining the speed of each gear may include the following steps:

[0182] 1) The tower crane lifting axis (Lift) has five speed settings. Set the speed to the highest setting (5) to control the tower crane's operation. Take actual measurements when the maximum speed is reached during operation. Collect data to a file during the measurement process, and select data from the stable high-speed interval during the tower crane's operation for calculation. Typically, if the tower crane operates at its highest speed and maintains a relatively constant speed for more than 3 seconds, with minimal speed changes or only slight vibrations during this period, it can be considered to be in a stable operating range. Take the average of the actual speeds within this stable range and use this average as the maximum speed of the Lift (MaxVel_Lift, m / s). For example, if 100 sampling points are obtained within 3 seconds, take the average of these 100 sampling points as the maximum speed. This maximum speed can be used as the speed for the highest speed setting. For the Turn and Swing axes, find the maximum speeds MaxVel_Turn (radians / second) and MaxVel_Swing in the same way when moving at the highest speed setting.

[0183] 2) Based on the actual speed of the highest gear of each axis and the corresponding Hertz value of the frequency converter, calculate the speed of each gear for each axis. The conversion formula is as follows:

[0184]

[0185] Among them, Max Hz This indicates the highest Hertz value; Max vel Indicates the highest gear speed; G1 Hz Indicates the Hertz value for level 1; G1 Vel This represents the speed in gear 1. Using the above formula, the speeds of other gears can be calculated from the measured speed of the highest gear, based on the linear proportional relationship between the Hertz value and the measured speed.

[0186] In one embodiment, determining the gear separation speed between adjacent operating gears based on the gear speeds of each operating gear of the tower crane includes:

[0187] The average speed of two adjacent operating gears is used as the gear separation speed between adjacent operating gears.

[0188] Based on the calculated speed of each gear position for each axis, the gear separation speed for each axis can be calculated. For example, if the Lift axis has 5 gears, then there are 5 gear separation speeds, denoted by Th1 to Th5. Th1 is the speed separation value between 0 speed and 1st gear. That is, if the planned speed of a trajectory point on the original planned trajectory exceeds Th1 but is less than Th2, the planned speed is replaced by the 1st gear speed G1vel, and the trajectory is discretized.

[0189] Each axis has a corresponding speed and a corresponding Hertz value for the inverter. Similar to setting speed intervals between speeds, Hertz values ​​between speeds can also be set. The Hertz interval between speed 0 and speed 1 is represented by Th1Hz. The value of Th1Hz can be preset within a reasonable range, such as 0.20Hz to 0.30Hz. In one example, Th1Hz is set to 0.25Hz by default. Th2Hz is taken as (G1Hz + G2Hz) / 2, which is the average of the Hertz values ​​of the two speeds. The Hertz intervals and speed intervals between other speeds can also be calculated by averaging. See also... Figure 5 The data calculation results show the gear speed and gear separation speed of each gear of the three axes: luffing, lifting, and slewing.

[0190] In one embodiment, obtaining the gear speed adapted to the planned speed based on the gear separation speed includes:

[0191] For each operating gear, the interval between the speeds of two gears adjacent to the speed of the gear is determined as the speed interval corresponding to the operating gear;

[0192] For each trajectory point on the original planned trajectory, if the planned speed value of the trajectory point is within the speed range, then the gear speed of the operating gear corresponding to the speed range is taken as the gear speed that matches the planned speed.

[0193] The gear-separation speed serves as a dividing value for assigning different speeds to different gears, allowing for the definition of the speed range corresponding to each operating gear. For example, a tower crane lifting shaft has three operating gears. Gear 1 has a speed of 0.5 m / s, gear 2 has a speed of 1 m / s, and gear 3 has a speed of 1.5 m / s. The gear-separation speed between gears 1 and 2 is 0.75 m / s, and the gear-separation speed between gears 2 and 3 is 1.25 m / s. Therefore, for gear 2, the interval between its two adjacent gear-separation speeds is 0.75 m / s to 1.25 m / s, which constitutes the speed range corresponding to gear 2. In one example, if the planned speed of a trajectory point in the original planned trajectory is 1.2 m / s, which falls within the speed range corresponding to gear 2, then the gear-separation speed of 1 m / s for gear 2 is used as the appropriate gear-separation speed to match the planned speed of 1.2 m / s. Assigning 1 m / s to the trajectory point means replacing the original planned speed of 1.2 m / s with the appropriate gear speed of 1 m / s, thus obtaining the discretized planned trajectory.

[0194] In one embodiment, the method further includes:

[0195] Based on different velocity directions, the original planned trajectory is divided into multiple segmented trajectories;

[0196] For each trajectory point on the segmented trajectory, the absolute value of the planned velocity of the trajectory point is extracted, and the velocity direction information of the trajectory point is saved;

[0197] Based on the gear separation speed, obtain the gear speed that matches the absolute value of the planned speed;

[0198] For each trajectory point on the segmented trajectory, the absolute value of the planned speed is replaced with the adapted gear speed to obtain the discretized segmented trajectory.

[0199] The velocity direction information is added to each segmented trajectory; the segmented trajectories are then combined to obtain the discretized planned trajectory.

[0200] In another example, the direction of the crane hook's velocity may change during crane operation. In kinematics, the direction of velocity is represented by a symbol. For example, if we assume upward is the positive direction, then the velocity is 4 m / s. 2 This indicates that the object is moving upwards with a speed of 4 m / s. 2 The speed is -5m / s 2 This indicates that the object is moving downwards with a speed of 5 m / s. 2In other words, the absolute value represents the magnitude of velocity, and the sign represents the direction of velocity. It's clear that the sign here has a different meaning than the positive and negative signs in mathematics. In mathematics, positive numbers are greater than negative numbers, and the sign reflects the numerical relationship. However, in kinematics, the sign of velocity is unrelated to its magnitude; only the absolute value represents the magnitude. Therefore, in trajectory discretization, only the absolute value of velocity can be processed. For reciprocating motion, the motion can be segmented according to different directions. For each segment, the absolute value of velocity is extracted and discretized; simultaneously, the sign information of the velocity is saved. After converting the velocity value of each segment into the corresponding gear speed, the sign information of the velocity is added to each segment trajectory. Finally, all the segment trajectories are integrated into a single overall trajectory.

[0201] For example, a certain direction can be set as the positive direction of motion. The sign of the continuous velocity in the planned trajectory is represented by a trajectory velocity symbol. Assuming the upward direction is set as positive on the ascending / descending axis, if the velocity direction is upward, the trajectory velocity symbol is positive; if the velocity direction is downward, the trajectory velocity symbol is negative. During trajectory discretization, the trajectory velocity symbol can be extracted first. For example, if there are 1000 trajectory points in the planned trajectory, the trajectory velocity symbols can be stored in an array with 1000 elements. Then, the planned velocity of each trajectory point in each segment is discretized as a positive value. If the planned trajectory is entirely negative, the negative values ​​are directly converted to positive values ​​and discretized using positive values. If the planned trajectory is entirely positive, it is also discretized using positive values. If the planned trajectory has both positive and negative directions, it is processed segment by segment according to different directions. Each segment of the trajectory in both the negative and positive directions undergoes a separate discretization process. For example, in a continuous planned trajectory, the first segment is positive, the middle segment is negative, and the last segment becomes positive again. At this point, the discretization process needs to be executed separately for the three trajectory segments mentioned above, and the process is executed three times in total. The trajectory velocity symbols of the trajectory points of the three trajectory segments are stored in three arrays respectively. After segmented processing, that is, after the continuous planned speed is converted into the corresponding gear speed, the motion direction information is added to each segment trajectory, and the segmented trajectories are combined into a total running trajectory.

[0202] Figure 6 This is a schematic diagram of the discrete algorithm flow of an embodiment of the tower crane motion control method provided in this application. Figure 6As shown, during trajectory discretization, the trajectory velocity symbols are first temporarily stored in an array for later use, and the absolute values ​​of the velocities of all trajectory points are taken. Then, iterative processing is performed on each segment of the trajectory. During each iteration, the gear-separating speed can be appropriately adjusted. The gear-separating speed can be linearly increased or decreased, for example, increasing both TH1 and TH2 by 1% to adapt the gear speed to the original planned speed. The gear-separating speed TH is adjusted in each iteration until the error accuracy requirement is met. In one example, an upper limit can be set for the number of iterations, for example, limiting the number of iterations to a maximum of 20,000. If no match is found after more than 20,000 iterations and the accuracy requirement is not met, the program exits and returns an error. See also... Figure 4 If the number of iterations does not exceed the limit, then according to the gear-separated speed TH, the gear speed is assigned to the trajectory point of the speed range corresponding to the planned speed value in this gear.

[0203] The ultimate goal of trajectory discretization is to ensure positional accuracy. Therefore, the path difference between the discretized trajectory and the undiscretized trajectory must be sufficiently small to meet the accuracy requirements. In one embodiment, the method further includes:

[0204] Based on the planned speed corresponding to each trajectory point on the original planned trajectory, the first distance is obtained by integral calculation;

[0205] Based on the gear speed adapted to each trajectory point on the discretized planned trajectory, the second distance is obtained by integral calculation.

[0206] If the difference between the first route and the second route is less than a preset threshold, the endpoint of the second route is corrected based on the endpoint of the first route.

[0207] See Figure 6 The second distance is obtained by integrating the speed of each trajectory point on the discretized planned trajectory and calculating the speed of the corresponding gear. The first distance is obtained by integrating the planned speed of each trajectory point on the original planned trajectory. The difference between the first and second distances is the distance difference L. If the distance difference L is less than a preset threshold, the discretization result meets the error requirement. In this case, the discretized speed can be integrated to calculate the discretized position of each trajectory point, and then the endpoint correction can be performed on the discretized trajectory. For example, if the displacement of the trajectory before discretization is 100 meters and the displacement after discretization is 99.8 meters, the position of the last trajectory point is corrected during endpoint correction, forcing the distance between the last trajectory point and the starting point to 100 meters. Through endpoint correction, the tower crane can accurately reach the predetermined endpoint, achieving the predetermined operational goal.

[0208] In one embodiment, the method further includes:

[0209] When the distance difference is greater than or equal to a preset threshold and the distance difference diverges, the appropriate gear speed for the specified trajectory point is downshifted in a predetermined order.

[0210] See Figure 6 After discretization, the distance is calculated by integrating the speeds of the discretized trajectory points and the speeds of the undiscrete trajectory points, yielding the distance difference L. If the distance difference L does not meet the accuracy requirements, it is determined whether L is diverging. If the value of the distance difference L increases, meaning the position of the discretized trajectory point exceeds the originally planned position, then the distance difference L is determined to be diverging. In this case, the appropriate speed for each trajectory point is downgraded. Specifically, the appropriate speed for a specified trajectory point is downgraded sequentially according to a predetermined order.

[0211] Specifically, adjustments can be made by downshifting from the highest gear to the lowest. For example, if the highest gear is 3rd, downshifting can be performed first, lowering the speed point at 3rd gear to 2nd gear. If the distance difference L still does not meet the error requirement after all speed points at 3rd gear have been downshifted to 2nd gear, then downshifting can be performed again at 2nd gear. This adjustment process is repeated sequentially from highest to lowest gear until the distance difference L meets the error requirement.

[0212] Furthermore, during the downgrading adjustment of the highest gear, the downgrading process starts from both ends of the highest gear trajectory point's index interval and proceeds towards the middle, downgrading one by one. For example, first, trajectory point A, located at one end of the index interval, is downgraded to gear 2, and then it is checked whether the distance difference L meets the error requirement. If it does not meet the requirement, then trajectory point B, located at the other end of the index interval, is downgraded to gear 2, and then the distance difference L is checked again. If it still does not meet the requirement, the process continues, downgrading the trajectory points adjacent to A, then the trajectory points adjacent to B, to gear 2, until the accuracy requirement is met, ultimately matching the discrete value of each trajectory point.

[0213] For example, if there are 5000 trajectory points that need to be discretized in the planned trajectory, each trajectory point is marked with a serial number, and this serial number information is stored in an array. During downshifting, all discretized trajectory points need to be retrieved, starting with the highest gear. In one example, the highest gear for downshifting is 3rd gear, so the array needs to be searched for trajectory points with a speed of 3rd gear. The serial numbers of these trajectory points are within a range, with the smallest serial number on the left and the largest serial number on the right. Assume that 3rd gear corresponds to the range between the 800th and 900th trajectory points in the entire trajectory. The minimum serial number in this range is 800, and the maximum serial number is 900. Then, starting from both ends of the range, downshifting is performed on each trajectory point towards the middle. Specifically, the 800th trajectory point can be downshifted to 2nd gear first, and then the distance difference L can be checked to see if it meets the error requirement. If the requirements are not met, the 900th trajectory point is downgraded to level 2, and then the distance difference L is checked to see if it meets the error requirement. If it still does not meet the requirement, the 801st trajectory point, the 899th trajectory point, and so on, are downgraded to level 2 until the accuracy requirement is met, ultimately matching the discrete value of each trajectory point. This method of downgrading from both ends of the interval towards the middle is beneficial for the continuous and stable operation of the tower crane speed, maintaining good motion characteristics throughout the entire control process.

[0214] In one embodiment, the method further includes:

[0215] If the distance difference is greater than or equal to a preset threshold and the distance difference does not diverge, the gear separation speed is adjusted according to the distance difference.

[0216] See Figure 6 When the distance difference L does not meet the accuracy requirements, it is determined whether the distance difference L is diverging. If the value of the distance difference L is getting smaller and smaller, it is determined that the distance difference L is not diverging. In this case, the gear separation speed TH is converged and offset according to the distance difference L, so that the distance difference L continues to shift in the direction of decreasing, thereby ensuring that the end point of the trajectory is not deviated. Specifically, the speed TH at the separation point of each gear is adjusted linearly. If the error of the distance difference L is large, TH can be increased slightly. For example, increasing each TH by one-thousandth will shorten the distance difference L. If the difference between the first distance before discretization and the second distance after discretization is greater than 0, the discretized position has not reached the expected position, so the value of TH is increased. If the difference between the first distance before discretization and the second distance after discretization is less than or equal to 0, the value of TH is decreased. Regardless of whether the value of TH is increased or decreased, the goal of the adjustment is to make the absolute value of the distance difference gradually decrease. If the absolute value of the distance difference has a tendency to increase, the distance difference is diverging, and then it is adjusted according to... Figure 6The divergent processing flow continues, that is, the appropriate gear speed for the specified trajectory point is downshifted in a predetermined order.

[0217] In summary, when the distance difference L does not meet the accuracy requirements, corresponding processing is carried out for both cases of distance difference divergence and non-divergence until the error meets the accuracy requirements. Finally, a suitable speed is matched for each trajectory point in the original planned trajectory, so that the control output is adapted to the speed-based control method, which improves the control accuracy of the unmanned tower crane and effectively reduces safety risks.

[0218] In one embodiment, after shifting and misaligning the trajectory points on the original planned trajectory along each axis to align the start times in each axis, the method further includes:

[0219] During the operation of the tower crane, it is determined whether the motion state in the axial direction meets the corresponding PID control start-up conditions; wherein, the corresponding PID control start-up conditions are set in advance according to the motion characteristics in the axial direction.

[0220] When the motion state in the axial direction meets the corresponding PID control start-up conditions, the target speed planned for the next trajectory point is compensated; and the compensated target speed is discretized according to the operating gear of the tower crane to obtain the gear speed that matches the compensated target speed; the matched gear speed is used as the command speed issued for the next trajectory point.

[0221] By regulating the movement of the tower crane using PID control, the endpoint alignment process in actual operation can be simulated. Specific regulation methods include PID control with step-by-step adjustments and PID control with continuous speed. The adjustment method for PID control with step-by-step adjustments is as follows: Figure 7 As shown.

[0222] See Figure 7 In one embodiment, the method further includes:

[0223] Step S710: During the operation of the tower crane, determine whether the motion state in the axial direction meets the corresponding PID control start-up conditions; wherein, the corresponding PID control start-up conditions are preset according to the motion characteristics in the axial direction.

[0224] Step S720: When the motion state in the axial direction meets the corresponding PID control start-up conditions, the compensation speed is obtained based on the position deviation between the target position and the current position of the current trajectory point.

[0225] Step S730: Determine the compensated target speed of the next trajectory point based on the compensated speed and the target speed planned for the next trajectory point;

[0226] Step S740: Discretize the compensated target speed according to the tower crane's operating gear to obtain a gear speed that matches the compensated target speed; use the matched gear speed as the command speed for the next trajectory point.

[0227] In step S710, during the operation of the tower crane, it is determined whether the motion state in each axis direction meets the corresponding PID control start-up conditions. These PID control start-up conditions are pre-set based on the motion characteristics in each axis direction. The PID control start-up conditions differ for each axis. For example, the PID control start-up condition in the lifting direction can be real-time tracking and PID adjustment throughout the entire process; the PID control start-up condition in the slewing direction can be that the PID adjustment speed is only activated when approaching the end of the trajectory, when the actual speed is low and the position deviation is large; and the PID control start-up condition in the luffing direction can be that the PID adjustment speed is activated only when the speed at the last trajectory point has just been issued.

[0228] In step S720, when the motion state along the axis meets the corresponding PID control start-up conditions, the compensation speed is obtained based on the target position and the position deviation of the current trajectory point. During lifting, slewing, and luffing, the position deviation is calculated for each axis. The PID calculates the position deviation of the current trajectory point based on the target position and the current actual position of that axis. Then, the speed to be compensated, i.e., the compensation speed, is calculated based on the position deviation. Specifically, the compensation speed is obtained by dividing the position deviation by the unit time.

[0229] The original planned trajectory may include several trajectory points, each corresponding to a control cycle. The control command for the next trajectory point is about to be issued in the current cycle. The target speed for the next trajectory point is calculated by the planner. During tower crane operation, a position deviation is calculated based on the actual position collected in the current cycle and the target position of the current cycle. The compensation speed is the speed required to compensate for the position deviation of the current cycle. The PID controller performs compensation processing to obtain the compensation speed. The compensation speed is adjusted to the target speed of the next cycle and issued as a control command. In step S730, for each axis, based on the compensation speed obtained in step S720 and the planned target speed of the next trajectory point, the compensated target speed of the next trajectory point is determined.

[0230] For each axis, the tower crane's unmanned control system stores the speed corresponding to each gear position for that axis. In step S740, based on the correspondence between gear positions and speeds, it is determined which gear position each axis should operate at in its running mechanism to achieve the target speed. The compensated target speed is discretized according to the tower crane's operating gears to obtain the gear speed that matches the compensated target speed. Then, the matched gear speed is used as the command speed for the next trajectory point, thereby adjusting the running speed of each axis's running mechanism.

[0231] The embodiments of this application set corresponding PID control start conditions according to the motion characteristics of each axis in the axial direction, and combined PID control with trajectory discretization processing, thereby making the tower crane operation control more precise and stable and effectively reducing safety risks.

[0232] Figure 8 This is a PID control diagram of one embodiment of the tower crane motion control method provided in this application. Figure 8 As shown, R(k) represents the target position of the current trajectory point, Y(k) represents the current position in this cycle, and the controlled object is a tower crane. First, the position deviation between the target position of the current trajectory point and the current position in this cycle is calculated and input to the PID control module. The PID control module obtains the compensation speed based on the target position of the current trajectory point and the position deviation. The output of the feedforward loop is the planned target speed for the next trajectory point, i.e., the target speed before compensation. Then, based on the compensation speed and the planned target speed for the next trajectory point, the compensated target speed for the next trajectory point is determined. The resultant speed of the compensation speed and the planned target speed for the next trajectory point can be used as the compensated target speed. The compensated target speed is discretized according to the tower crane's operating gear to obtain the gear speed adapted to the compensated target speed. Finally, the adapted gear speed is output to the controlled object to control it.

[0233] Figure 9 This is a schematic diagram of the startup process of an embodiment of the tower crane motion control method provided in this application. Figure 9 As shown, for a tower crane based on gear control, there is a delay between the issuance of a gear and the start of movement for each axis. Therefore, the PID controllers for all three axes need to delay for a period of time before starting. This time reflects the start-up delay characteristics of each axis. Figure 9 The purpose of the start-up adjustment is to adjust the start-up delay time for each axis individually. For each axis, the following can be performed when the tower crane starts: Figure 9 The process shown is divided into the following three stages for startup and adjustment.

[0234] In one embodiment, the method further includes:

[0235] If the current time is less than the start-up delay time, the starting point in the original planned trajectory is used as the target position for PID control.

[0236] Here, the target position refers to the target position R(K) of the PID control. If the tower crane has not started when the current time is less than the start delay time, the PID adjustment point is the starting point, and the target point is the starting point. If the PID is instructed to find the target position at the very beginning before the tower crane has actually started moving, the PID will continuously accumulate the target speed, which may result in excessive compensation speed. This accumulation is meaningless and can easily cause overshoot. Therefore, the control strategy of this embodiment is to not perform PID control during the delay start time.

[0237] In one embodiment, the method further includes:

[0238] If the current time is greater than or equal to the start-up delay time and all trajectory points have been sent, the endpoint in the original planned trajectory will be used as the target position for PID control.

[0239] After all trajectory points have been sent, the PID controller needs to be adjusted and control continues for a period of time. In other words, there is a control delay after all trajectory points have been sent.

[0240] In one embodiment, the method further includes:

[0241] If the current time is greater than or equal to the start delay time and the trajectory point has not been completely sent, the current trajectory point will be used as the target position for PID control.

[0242] During the intermediate period after the tower crane starts but before the trajectory points are fully distributed, the current trajectory point is used as the adjustment point for PID control.

[0243] In the above startup process, a series of target positions are staggered overall. For example, the original planned trajectory has 1000 trajectory points. The time interval between each trajectory point is 1 second, so the 1000 points need to run for 1000 seconds. If the startup delay is 10 seconds, then from 0 to 10 seconds, the starting point is used as the PID controller's R(k). R(k) is the target position of the current trajectory point's PID control. From 10 seconds to 10¹⁰ seconds, the current trajectory point is used as the target position for PID control. After 10¹⁰ seconds, the target endpoint is used as the target position for PID control. In the above startup process, a series of target positions are staggered by 10 seconds in the overall control.

[0244] The delay is a characteristic of tower cranes; therefore, directly issuing a target speed will not immediately initiate movement. It requires a delay before it begins to move. It is not advisable to adjust the PID controller while the tower crane is not moving. Instead, wait until the start-up delay has elapsed before adjusting the PID to initiate its target point. Initiating the PID means assigning values ​​to the target points as actual trajectory points using a staggered approach. In the example above, the first 10 target points are the starting points; the 1000th trajectory point becomes the 1010th trajectory point; the 1010th target point is the original 1000th trajectory point. After the 1010th target point, the endpoint is continuously adjusted. In this delayed staggered process, if all trajectory points have been issued, the endpoint is adjusted; otherwise, the trajectory points are adjusted one by one.

[0245] In conclusion, Figure 9 The startup adjustment for each axis is performed in three stages, each with its own startup delay time. These three stages are: 1) When the current time is less than the startup delay time, PID control is applied to the starting point; 2) When the current time is greater than or equal to the startup delay time and the trajectory points have not been fully distributed, PID control is applied to the current trajectory point; 3) When the current time is greater than or equal to the startup delay time and all trajectory points have been distributed, PID control is applied to the ending point. After adjusting the startup delay time for each axis individually, since the startup delay times for each axis are different, further adjustments are needed... Figure 2 The process shown aligns the start-up times of each axis, ensuring that axes that start slower start first and axes that start faster start later, so that all axes reach the desired position at the same time.

[0246] In one embodiment, the corresponding PID control start-up conditions, pre-set according to the motion characteristics in the axial direction, include:

[0247] When the axis direction is the lifting direction, the corresponding PID control start condition is: PID control is performed throughout the entire operation of the tower crane.

[0248] Because the tower crane ropes are heavy, sending the same speed setting to the inverter results in varying weights for different rope lengths, thus causing the actual speed to change continuously. Therefore, real-time PID control is required throughout the entire process.

[0249] like Figure 10As shown, the PID controller first calculates the compensation speed corresponding to the position deviation, and then calculates the compensated target speed for the next trajectory point. The calculation formula is as follows: Target Speed ​​= Trajectory Speed ​​+ Compensation Speed. Where, the trajectory speed is the planned target speed for the trajectory point. If the target speed is less than speed level 1, output speed level 0. If the target speed is greater than or equal to speed level 1, determine if the target speed is less than speed level 2. If the target speed is less than speed level 2, output speed level 1. If the target speed is greater than or equal to speed level 2, determine if the target speed is less than speed level 3. If the target speed is less than speed level 3, output speed level 2. If the target speed is greater than or equal to speed level 3, determine if the target speed is less than speed level 4. If the target speed is less than speed level 4, output speed level 3. If the target speed is greater than or equal to speed level 4, determine if the target speed is less than speed level 5. If the target speed is less than speed level 5, output speed level 4. If the target speed is greater than or equal to speed level 5, output speed level 5.

[0250] In one embodiment, the corresponding PID control start-up conditions, pre-set according to the motion characteristics in the axial direction, include:

[0251] When the axis direction is the rotation direction, the corresponding PID control start conditions are: the actual speed is less than the preset gear speed, the planned target speed is zero, and the position deviation exceeds the preset first deviation threshold.

[0252] The slewing shaft of a tower crane is characterized by a relatively long acceleration time. In one example, the actual acceleration time for the tower crane slewing shaft to accelerate from speed 0 to speed 4 is 11 seconds. The PID control cycle is 0.1 seconds. Using PID control during motion will result in significant lag and overshoot.

[0253] In the PID control start-up conditions corresponding to the above rotation direction, the planned target speed is zero, which is the moment when the tower crane's trajectory approaches the end point. In the example above, the preset speed can be set to speed level 1; the preset first deviation threshold is set according to the system accuracy, for example, it can be ±0.5 degrees. To avoid overshoot, the PID controller only starts adjusting when the actual speed is less than speed level 1, the position deviation exceeds the preset first deviation threshold, and the trajectory is approaching the end point.

[0254] In addition, the boom of a tower crane has particularly large inertia. The slewing shaft cannot output speed at level 1 for an extended period, as this would make it difficult for the tower crane to stop. Therefore, the speed output can be stopped immediately after reaching level 1, creating a slow-motion-like effect, resulting in gentler acceleration and reduced transient vibration. The tower crane's frequency converter has a characteristic that, despite significant lag, it will still try to match the position produced by level 1. Therefore, the above adjustment method is a method for adjusting a controlled object with large lag. After outputting speed at level 1, the tower crane will gradually accelerate, and once it reaches level 1, no further speed commands will be issued. This way, the tower crane speed is maintained at or below level 1 during the adjustment process, ensuring that the speed adjustment remains within level 1 or at a relatively short duration.

[0255] like Figure 11 As shown, the process first determines whether the current operating state of the tower crane meets the PID control start-up conditions corresponding to the rotation direction, i.e., whether the actual speed is less than level 1, the planned target speed is zero, and the position deviation exceeds the preset first deviation threshold. If not, PID adjustment is not performed, and the tower crane's operating level is directly discretized to output the speed corresponding to the track speed (the planned target speed of the track point). If yes, the PID calculates the compensation speed corresponding to the position deviation, and then calculates the compensated target speed for the next track point. The calculation formula is as follows: Target speed = Track speed + Compensation speed. Where, the track speed is the planned target speed of the track point. If the target speed is less than level 1, the speed is output as level 0. If the target speed is greater than or equal to level 1, the speed is output as level 1.

[0256] In one embodiment, the corresponding PID control start-up conditions, pre-set according to the motion characteristics in the axial direction, include:

[0257] When the axis direction is the amplitude direction, the corresponding PID control start condition is: the planned target speed is less than the preset gear speed and the position deviation exceeds the preset second deviation threshold.

[0258] The preset second deviation threshold is set according to the system accuracy, for example, it can be 0.1 meters.

[0259] The adjustment of the luffing direction takes effect immediately after the trajectory speed stops. In one example, the tower crane luffing shaft has three speed settings, accelerating from speed 0 to speed 3 in just 2.5 seconds. Due to the large speed increments, frequent gear changes during operation are not advisable, as this can increase transient vibrations and cause swaying. If speed 0 is output during operation, the tower crane speed will immediately drop to 0. In this case, if speed 1 is then output, the crane will decelerate and then accelerate again, easily leading to instability and swaying. For the tower crane luffing shaft, the speed can be adjusted at the last trajectory point after the speed is issued, allowing for the final speed adjustment. The purpose of this adjustment is to prevent a rapid deceleration from speed 3 to 0 during deceleration. If there is a positional deviation, speed 1 or speed 2 can be used.

[0260] like Figure 12 As shown, the process first determines whether the current operating state of the tower crane meets the PID control start-up conditions corresponding to the luffing direction, i.e., whether the trajectory speed (planned target speed) is less than level 1 and the position deviation exceeds the preset second deviation threshold. If not, no PID adjustment is performed, and the tower crane's operation is directly discretized, outputting the speed corresponding to the trajectory speed. If yes, the PID calculates the compensation speed corresponding to the position deviation, and then calculates the compensated target speed for the next trajectory point. The calculation formula is as follows: Target speed level = Trajectory speed + Compensation speed. Where, the trajectory speed is the planned target speed of the trajectory point. If the target speed is less than level 1, the speed is output at level 0. If the target speed is greater than or equal to level 1, it is determined whether the target speed is less than level 2. If the target speed is less than level 2, the speed is output at level 1. If the target speed is greater than or equal to level 2, it is determined whether the target speed is less than level 3. If the target speed is less than level 3, the speed is output at level 2. If the target speed is greater than or equal to level 3, the speed is output at level 3.

[0261] See Figure 7 and Figure 13 In one implementation, Figure 7 In step S740, the compensated target speed is discretized according to the operating gear of the tower crane to obtain a gear speed that matches the compensated target speed. Specifically, this may include:

[0262] Step S1310: Determine the gear separation speed between adjacent operating gears based on the gear speed of each operating gear of the tower crane.

[0263] Step S1320: Obtain the compensated target velocity for each trajectory point;

[0264] Step S1330: Based on the gear separation speed, obtain the gear speed that matches the compensated target speed.

[0265] Step S1340: For each trajectory point on the original planned trajectory, replace the compensated target speed with the adapted gear speed to obtain the discretized planned trajectory.

[0266] The controller generates the original planned trajectory of the tower crane hook and determines the compensated target speed for each trajectory point based on PID control. In order to adapt the compensated target speed of each trajectory point to the speed of each operating gear, the compensated target speed of each trajectory point needs to be assigned to the speed of each gear one by one.

[0267] In step S1310, the gear separation speed between two adjacent operating gears is determined based on the gear speed of each operating gear of the tower crane. If the compensated target speed of a certain trajectory point is less than or equal to the gear separation speed, the relatively lower gear speed is assigned to the trajectory point to obtain the discretized planned trajectory; if the compensated target speed of a certain trajectory point is greater than the gear separation speed, the relatively higher gear speed is assigned to the trajectory point to obtain the discretized planned trajectory.

[0268] In step S1320, the compensated target speed for each trajectory point is obtained. In step S1330, based on the gear separation speed determined in step S1310, the gear speed adapted to the compensated target speed for each trajectory point is obtained. If the compensated target speed of a trajectory point is between two adjacent gear speeds, the compensated target speed is compared with the gear separation speed between the two adjacent gear speeds. If the compensated target speed is less than or equal to the gear separation speed, the gear speed adapted to the compensated target speed of the trajectory point is a relatively lower gear speed; if the compensated target speed is greater than the gear separation speed, the gear speed adapted to the compensated target speed of the trajectory point is a relatively higher gear speed. For example, if the compensated target speed of a trajectory point is 0.8 m / s, and its speed value is between gear 1 and gear 2 and greater than the gear separation speed between gear 1 and gear 2 (0.75 m / s), then the gear speed adapted to the compensated target speed of the trajectory point is the gear speed of 2 (1 m / s).

[0269] In step S1340, for each trajectory point on the original planned trajectory, the compensated target speed in the original planned trajectory is replaced with the adapted gear speed obtained in step S1330 to obtain the discretized planned trajectory.

[0270] exist Figures 4 to 6 In the example, the object of trajectory discretization is the "planned speed". For each trajectory point on the original planned trajectory, the planned speed is replaced with an appropriate gear speed, resulting in the discretized planned trajectory. Figure 13In the example, a similar method is used for trajectory discretization, the main difference being that the discretized object, "planned speed," is replaced with "compensated target speed." For each trajectory point on the original planned trajectory, the compensated target speed is replaced with an appropriate gear speed, resulting in the discretized planned trajectory. About Figure 13 For examples of the beneficial effects of discretization or the technical problems it solves, please refer to [reference needed]. Figures 4 to 6 The descriptions of the corresponding methods in the examples are not repeated here.

[0271] like Figure 14 As shown, this application also provides an embodiment of a tower crane motion control device. For the beneficial effects of this device or the technical problems it solves, please refer to the descriptions in the methods corresponding to each device, or to the descriptions in the invention summary; they will not be repeated here.

[0272] In an embodiment of the tower crane motion control device, the device includes:

[0273] The first acquisition unit 100 is used to acquire the original planning trajectory from the tower crane's planner;

[0274] The second acquisition unit 200 is used to acquire the start-up delay time of the tower crane in each axis direction;

[0275] The delay processing unit 300 is used to perform overall translation and misalignment of the trajectory points on the original planned trajectory in each axis direction according to the start delay time in each axis direction, so as to align the start time in each axis direction and make each axis reach the same desired position at the same time.

[0276] like Figure 15 As shown, in one embodiment, the device further includes a slewing control unit 400, the slewing control unit 400 being used for:

[0277] During tower crane operation, determine whether the tower crane is moving in the direction of its slewing axis;

[0278] When there is movement in the direction of the slewing axis, the brake in the direction of the slewing axis is released at a predetermined time before the command speed in the direction of the slewing axis is issued.

[0279] In one embodiment, the slewing control unit 400 is further configured to:

[0280] When there is no movement in the direction of the slewing axis, the movement in the direction of the slewing axis is controlled by jogging the brake.

[0281] like Figure 15As shown, in one embodiment, the device further includes a hook lowering control unit 500, which is used for:

[0282] Determine whether the tower crane's slewing axis is in the correct position.

[0283] When the object is in the correct operating position in the direction of the slewing axis, the hook is lowered.

[0284] like Figure 15 As shown, in one embodiment, the device further includes a discrete processing unit 600, which is used to: after obtaining the original planning trajectory from the tower crane's planner, perform gear-adaptation on the planning speed of each trajectory point on the original planning trajectory of the tower crane to obtain a discretized planning trajectory.

[0285] The delay processing unit 300 is further configured to: shift and misalign the trajectory points on the discretized planned trajectory as a whole according to the start-up delay time in each axis direction, so as to align the start-up time in each axis direction.

[0286] In one embodiment, the discrete processing unit 600 is used for:

[0287] Determine the speed separation between adjacent operating gears based on the speed of each operating gear of the tower crane.

[0288] Obtain the planning velocity of each trajectory point on the original planned trajectory;

[0289] Based on the gear separation speed, the gear speed that matches the planned speed is obtained;

[0290] For each trajectory point on the original planned trajectory, the planned speed is replaced with the adapted gear speed to obtain the discretized planned trajectory.

[0291] like Figure 15 As shown, in one embodiment, the device further includes a PID control unit 700, the PID control unit 700 being used for:

[0292] During the operation of the tower crane, it is determined whether the motion state in the axial direction meets the corresponding PID control start-up conditions; wherein, the corresponding PID control start-up conditions are set in advance according to the motion characteristics in the axial direction.

[0293] When the motion state in the axial direction meets the corresponding PID control start-up conditions, the target speed planned for the next trajectory point is compensated; and the compensated target speed is discretized according to the operating gear of the tower crane to obtain the gear speed that matches the compensated target speed; the matched gear speed is used as the command speed issued for the next trajectory point.

[0294] Figure 16 This is a schematic structural diagram of a computing device 900 provided in an embodiment of this application. The computing device 900 includes: a processor 910, a memory 920, and a communication interface 930.

[0295] It should be understood that Figure 16 The communication interface 930 in the computing device 900 shown can be used to communicate with other devices.

[0296] The processor 910 can be connected to the memory 920. The memory 920 can be used to store the program code and data. Therefore, the memory 920 can be a storage unit inside the processor 910, an external storage unit independent of the processor 910, or a component that includes both the storage unit inside the processor 910 and the external storage unit independent of the processor 910.

[0297] Optionally, the computing device 900 may also include a bus. The memory 920 and communication interface 930 can be connected to the processor 910 via the bus. The bus can be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, etc. The bus can be divided into an address bus, a data bus, a control bus, etc.

[0298] It should be understood that in the embodiments of this application, the processor 910 may be a central processing unit (CPU). The processor may also be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor. Alternatively, the processor 910 may employ one or more integrated circuits to execute relevant programs to implement the technical solutions provided in the embodiments of this application.

[0299] The memory 920 may include read-only memory and random access memory, and provides instructions and data to the processor 910. A portion of the processor 910 may also include non-volatile random access memory. For example, the processor 910 may also store device type information.

[0300] When the computing device 900 is running, the processor 910 executes the computer execution instructions in the memory 920 to perform the operation steps of the above method.

[0301] It should be understood that the computing device 900 according to the embodiments of this application can correspond to the corresponding subject in executing the methods according to the various embodiments of this application, and the above and other operations and / or functions of each module in the computing device 900 are respectively for implementing the corresponding processes of the methods of this embodiment. For the sake of brevity, they will not be described in detail here.

[0302] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0303] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0304] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0305] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0306] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0307] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0308] This application also provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, performs a tower crane motion control method, the method including at least one of the solutions described in the above embodiments.

[0309] The computer storage medium in this application embodiment can be any combination of one or more computer-readable media. A computer-readable medium can be a computer-readable signal medium or a computer-readable storage medium. For example, a computer-readable storage medium can be, but is not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of computer-readable storage media (a non-exhaustive list) include: an electrical connection having one or more wires, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof. In this document, a computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device.

[0310] Computer-readable signal media may include data signals propagated in baseband or as part of a carrier wave, carrying computer-readable program code. Such propagated data signals may take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. Computer-readable signal media may also be any computer-readable medium other than computer-readable storage media, capable of sending, propagating, or transmitting programs for use by or in connection with an instruction execution system, apparatus, or device.

[0311] The program code contained on a computer-readable medium may be transmitted using any suitable medium, including, but not limited to, wireless, wire, optical fiber, RF, etc., or any suitable combination thereof.

[0312] Computer program code for performing the operations of this application can be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, and C++, and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving remote computers, the remote computer can be connected to the user's computer via any type of network, including a local area network (LAN) or a wide area network (WAN), or it can be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0313] Note that the above are merely preferred embodiments and the technical principles employed in this application. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present application has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, all of which fall within the scope of protection of the present invention.

Claims

1. A method for controlling the motion of a tower crane, characterized in that, include: Obtain the original planning trajectory from the tower crane's planner; Obtain the start-up delay time of the tower crane in each axis direction; According to the start-up delay time in each axis direction, the trajectory points on the original planned trajectory are shifted and misaligned as a whole in each axis direction to align the start-up time in each axis direction, so that each axis reaches the same desired position at the same time.

2. The method according to claim 1, characterized in that, The method further includes: During tower crane operation, determine whether the tower crane is moving in the direction of its slewing axis; When there is movement in the direction of the slewing axis, the brake in the direction of the slewing axis is released at a predetermined time before the command speed in the direction of the slewing axis is issued.

3. The method according to claim 2, characterized in that, The method further includes: When there is no movement in the direction of the slewing axis, the movement in the direction of the slewing axis is controlled by jogging the brake.

4. The method according to claim 1, characterized in that, The method further includes: Determine whether the tower crane's slewing axis is in the correct position. When the object is in the correct operating position in the direction of the slewing axis, the hook is lowered.

5. The method according to any one of claims 1 to 4, characterized in that, After obtaining the original planning trajectory from the tower crane's planner, the method further includes: adapting the planning speed of each trajectory point on the original planning trajectory of the tower crane to a gear to obtain a discretized planning trajectory; The step of translating and misaligning the trajectory points on the original planned trajectory in each axial direction to equalize the start time in each axial direction further includes: translating and misaligning the trajectory points on the discretized planned trajectory according to the start delay time in each axial direction to equalize the start time in each axial direction.

6. The method according to claim 5, characterized in that, The process of adapting the planned speed of each trajectory point on the original planned trajectory of the tower crane to the appropriate gear to obtain a discretized planned trajectory includes: Determine the speed separation between adjacent operating gears based on the speed of each operating gear of the tower crane. Obtain the planning velocity of each trajectory point on the original planned trajectory; Based on the gear separation speed, the gear speed that matches the planned speed is obtained; For each trajectory point on the original planned trajectory, the planned speed is replaced with the adapted gear speed to obtain the discretized planned trajectory.

7. The method according to any one of claims 1 to 4, characterized in that, After translating and misaligning the trajectory points on the original planned trajectory along each axis to align the start times in each axis, the method further includes: During the operation of the tower crane, it is determined whether the motion state in the axial direction meets the corresponding PID control start-up conditions; wherein, the corresponding PID control start-up conditions are set in advance according to the motion characteristics in the axial direction. When the motion state in the axial direction meets the corresponding PID control start-up conditions, the target speed planned for the next trajectory point is compensated; and the compensated target speed is discretized according to the operating gear of the tower crane to obtain the gear speed that matches the compensated target speed; the matched gear speed is used as the command speed issued for the next trajectory point.

8. A tower crane motion control device, characterized in that, include: The first acquisition unit is used to acquire the original planning trajectory from the tower crane's planner; The second acquisition unit is used to acquire the start-up delay time of the tower crane in each axis direction; The delay processing unit is used to perform overall translation and misalignment of the trajectory points on the original planned trajectory in each axis direction according to the start delay time in each axis direction, so as to align the start time in each axis direction and make each axis reach the same desired position at the same time.

9. A computing device, characterized in that, include: Communication interface; At least one processor connected to the communication interface; as well as At least one memory connected to the processor and storing program instructions that, when executed by the at least one processor, cause the at least one processor to perform the method of any one of claims 1-7.

10. A computer-readable storage medium having program instructions stored thereon, characterized in that, When the program instructions are executed by a computer, the computer performs the method described in any one of claims 1-7.

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